As electrophotographic color laser printers, there have been known tandem color laser printers which include four photosensitive drums which correspond to toner of four colors such as yellow, magenta, cyan and black.
Then, as a tandem color laser printer like this, there has been proposed, for example, an electrophotographic color image forming apparatus in which a plurality of process cartridges each including an electrophotographic photosensitive drum are drawn out or pushed into an apparatus main body in such a state that the process cartridges are supported on a movable member.